Clinical Outcomes of Transcatheter Aortic Valve Implantation (TAVI)

Abstract: Aortic stenosis (AS) is the most common valvular heart disease and most prevalent in the elderly. In the latest decades, a new method for replacement of the aortic valve: transcatheter aortic valve implantation (TAVI) has been introduced. This has enabled treatment of patients who were earlier not candidates for surgery, and has also led to a shift towards TAVI from open surgery for many patients with symptomatic AS. The aims of this thesis were to examine clinical outcomes after TAVI since its implementation in Sweden.In Study I we analysed the burden of disease after TAVI with focus on causes of hospitalisation, hospitalisation patterns and predictors of repeated hospitalisation. We identified that hospitalisations are common and from various indications. Heart failure was the most prevalent diagnosis and efforts should be made to reduce the burden of heart failure hospitalisations.In Study II we performed an external validation of an existing prediction model of risk for short-term hospitalisations after TAVI. The model underperformed in a Swedish setting and it is therefore not recommended for clinical use in its current state. The findings highlight the challenges of developing reliable models that are valid after transportation into a new setting.In Study III we investigated regional differences in availability to TAVI in Sweden with focus on regional procedure rates, short-term mortality and waiting times. The findings indicated no major regional differences. Hence, despite that Sweden is a geographically large and sparsely populated country the current system with a few specialised TAVI centres seems sufficient for providing national coverage of TAVI procedures.In Study IV we examined the need for and indications for coronary interventions after TAVI. We concluded that most patients do not need interventions after TAVI and in case an intervention is needed, the outcome is in a majority of cases successful, even though the success rates are lower than in patients without prior aortic valve replacement. The most common indication for intervention was non-ST elevation acute myocardial infarction and only a minority of patients underwent angiography at the time of a myocardial infarction post TAVI.